/*
 * This file is part of the GROMACS molecular simulation package.
 *
 * Copyright (c) 2010,2011,2012,2013,2014 by the GROMACS development team.
 * Copyright (c) 2016,2018,2019,2020, by the GROMACS development team, led by
 * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
 * and including many others, as listed in the AUTHORS file in the
 * top-level source directory and at http://www.gromacs.org.
 *
 * GROMACS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * GROMACS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GROMACS; if not, see
 * http://www.gnu.org/licenses, or write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
 *
 * If you want to redistribute modifications to GROMACS, please
 * consider that scientific software is very special. Version
 * control is crucial - bugs must be traceable. We will be happy to
 * consider code for inclusion in the official distribution, but
 * derived work must not be called official GROMACS. Details are found
 * in the README & COPYING files - if they are missing, get the
 * official version at http://www.gromacs.org.
 *
 * To help us fund GROMACS development, we humbly ask that you cite
 * the research papers on the package. Check out http://www.gromacs.org.
 */
/*! \file
 * \brief
 * Declares gmx::CommandLineParser.
 *
 * \author Teemu Murtola <teemu.murtola@gmail.com>
 * \inpublicapi
 * \ingroup module_commandline
 */
#ifndef GMX_COMMANDLINE_CMDLINEPARSER_H
#define GMX_COMMANDLINE_CMDLINEPARSER_H

#include <string>
#include <vector>

#include "gromacs/utility/classhelpers.h"

namespace gmx
{

class Options;

/*! \brief
 * Implements command-line parsing for Options objects.
 *
 * Typical usage (without error checking):
 * \code
   gmx::Options options("name", "description");
   // Fill up options

   gmx::CommandLineParser(&options).parse(&argc, argv);
   options.finish();
 * \endcode
 *
 * \inpublicapi
 * \ingroup module_commandline
 */
class CommandLineParser
{
public:
    /*! \brief
     * Creates a command-line parser that sets values for options.
     *
     * \param[in] options  Options object whose options should be set.
     * \throws  std::bad_alloc if out of memory.
     */
    explicit CommandLineParser(Options* options);
    ~CommandLineParser();

    /*! \brief
     * Makes the parser skip unknown options and keep them in \c argv.
     *
     * \param[in] bEnabled  Whether to skip and keep unknown options.
     * \returns   *this
     *
     * Setting this option to true has dual effect: unknown options are
     * silently skipped, and all recognized options are removed from
     * \c argc and \c argv in parse().  These effects should be easy to
     * separate into different flags if there is need for it.
     *
     * The default is false: unknown options result in exceptions and
     * \c argc and \c argv are not modified.
     *
     * Does not throw.
     */
    CommandLineParser& skipUnknown(bool bEnabled);

    /*! \brief
     * Makes the parser accept positional arguments
     *
     * \param[in] bEnabled  Whether to skip and keep positional arguments.
     * \returns   *this
     *
     * Arguments that are not options (ie. no leading hyphen), and
     * which come before all options are acceptable if this has
     * been enabled. If so, these arguments are left in \c argc
     * and \c argv in parse().
     *
     * The default is false: unknown leading arguments result in
     * exceptions and \c argc and \c argv are not modified.
     *
     * Does not throw.
     */
    CommandLineParser& allowPositionalArguments(bool bEnabled);

    /*! \brief
     * Parses the command line.
     *
     * \throws  std::bad_alloc if out of memory.
     * \throws  InvalidInputError if any errors were detected in the input.
     *
     * All command-line arguments are parsed, and an aggregate
     * exception with all the detected errors (including unknown
     * options, where applicable) is thrown in the end.
     *
     * If skipUnknown() was not called, or last called with a
     * false value, the input arguments are not modified. If
     * skipUnknown() was last called with a true value, only
     * unknown options will be retained in \c argc and \c argv.
     *
     * All positional arguments are retained in the argument list,
     * but such arguments must precede all options.
     *
     * \c argv[0] is never modified.
     *
     */
    void parse(int* argc, char* argv[]);

private:
    class Impl;

    PrivateImplPointer<Impl> impl_;
};

} // namespace gmx

#endif
